HERON, WHITE (Kotuku or White Egret)
This species, Egretta alba, though a rarity in New Zealand, is widely distributed and frequently abundant in many other countries. The local sub-species is also found from Australia to India. The New Zealand population is little more than a permanent beachhead established in the relatively recent past by birds wind-carried from the considerable population in eastern Australia. In this country only one breeding station is known and this was discovered in 1865 on the banks of the Waitangiroto Stream near Okarito in Westland. Here, up to about 20 pairs nest annually and later disperse with their young to perhaps as far north as Parengarenga Harbour and as far south as Stewart Island. In some years extra birds are carried over from Australia and temporarily swell the minute local population. Kotuku may then appear even on the Chathams and sub-Antarctic islands further south.
Their usual habitats are lake shallows, swamps, estuaries, and lagoons, where they wade gracefully about on their long legs (the birds stand about 3 ft high) searching for small fish which they impale with rapid and well-directed lunges of their sinuous necks and long-pointed bills. Few fishermen are more careful and patient than are the stalking kotuku. Shrimps, insects, and even small birds are also eaten.
In flight they retract their necks, trail their legs, and beat their wings with stately deliberateness. The plumage of both sexes is brilliant white, legs are black, and eye and bill yellow, except in the breeding season when the bill also becomes black. At this time there are fine dorsal plumes for which the species was once exploited. The voice is an unattractive croak.
Nest platforms are made of sticks and often overhang the water. A clutch consists of three to four pale-blue eggs. The young are ready to fly about six weeks after hatching. Kotuku have figured prominently in Maori legend as exemplars of rarity, grace, and beauty, and as inhabitants of the spirit world.
by Gordon Roy Williams, B.SC.(HONS.)(SYDNEY), Lecturer in Agricultural Zoology, Lincoln Agricultural College.